6
Figure 8: 1-stage thermostat, electric heating and cooling
application
Figure 9: 2-stage thermostat, electric heating and air
conditioning
2.5.1- Anticipator adjustment (if required) on thermostat
equipped with heat anticipator adjustment
Some thermostats are equipped with a heat anticipator that must
be adjusted according to the instructions supplied. This is to
ensure that the heating mode is comfortable and economical.
Generally speaking, on a single stage thermostat, a reading of
the current must be taken with an ammeter as follows:
1. Move the anticipator to its highest setting, rendering it
ineffective.
2. Remove the wire from the W1 terminal and connect an
ammeter between the terminal and the wire.
3. Call for heat by raising the set point on the thermostat and
allow the furnace to run for 3 to 4 minutes to reach its peak
output.
4. Once the current has stabilized, a reading should be taken
and the anticipator adjusted to that value. If longer heating
cycles are desired, the anticipator can be set to a higher
value
2.5.2- Air ducts
The ducts must be sized such a way as to accommodate the
specified airflow and the available static pressure. Refer to the
applicable local and/or national installation codes.
Insulate the ducts that lead through non-heated areas. Use
flexible supply and return air connectors to avoid the
transmission of vibration. To make the unit run even quieter, the
installer should:
a. Use two elbows between each outlet and the supply and
return air plenum;
b. Cover the vertical sections of the supply and return air duct
with soundproofing material;
c. Use baffles in short radius elbows;
d. Use flexible hangers to suspend the ducts.
A heat pump or an air conditioner can be added to this furnace,
in either the supply or return air duct. Carefully follow the
instructions provided with these appliances to ensure proper
installation and hook-up to the electric furnace. Refrigerant and
drainage pipes must in no way hinder access to the furnace
panels.
2.6- SUPPLY AIR ADJUSTMENTS
The supply air must be adjusted based on heating/air
conditioning output and the static pressure of the duct system.
For the desired airflow, refer to Table 1, as well as Table 3 and
Table 4 for the airflow based on static pressure.
For the adjustment of the airflow on heating mode, to obtain the
temperature rise described in the technical specification table
(Table 2), the red wire must be positioned on the terminal
corresponding to the LOW, MED-LOW, MED-HIGH or HIGH
blower speed.
For the adjustment of the airflow on air-cooling mode, to obtain
a sufficient airflow (350 to 450 CFM per Ton), the blue wire must
be positioned on the terminal corresponding to the LOW, MED-
LOW, MED-HIGH or HIGH blower speed.
Blower speeds are adjusted in factory for 0.5 inch static
pressure.
Table 1: Supply air adjustment on cooling mode
MOTOR HP
COOLING
CAPACITY
(0.5 ‘’ w.c.)
BLOWER SPEED
(Motor 120V)
BLOWER SPEED
(Motor 240V)
1/3
1.5
LOW
LOW
2.0
MED-LOW
LOW
2.5
MED-HIGH
MED
3.0
HIGH
HIGH
1.0
2.5
LOW
LOW
3.0
MED-LOW
MED-LOW
3.5
MED-LOW
MED-HIGH
4.0
MED-HIGH
MED-HIGH
5.0
HIGH
HIGH
If heating and air-cooling speeds are the same, the red wire and
the blue wire can be connected on the same terminal on the
motor.
